1. Field of the Invention
The invention relates to advertising displays, and specifically, to an apparatus for displaying a visual image along the surface of a segmented door, such as a rear roll-up door of a truck, trailer, or van.
2. The Prior Art
Referring to FIG. 1, segmented roll-up doors 110 are common in many industries, including the trucking and transport industries, and their typical designs are well known. A typical door 110 has a leading edge 112, an opposite trailing edge 114, a first edge 116 transverse to the leading edge 112, an opposite second edge 118, an exterior surface 120, and an opposite interior surface (not shown). Many such doors consist of a plurality of elongated segments 122 linked to each other along their longitudinal sides 124 to form a substantially continuous door 110. The leading and trailing edges of the door 110 correspond to the longitudinal side 124 of the elongated segments 122 that form the exterior segments of the door 110, while the first edge 116 and second edge 118 correspond to the latitudinal edges 126 of the plurality of elongated segments 122. Because of its linked construction, the door 110 is flexible along the axis corresponding to the direction of the longitudinal sides 124 of the elongated segments 122. As a result, such doors 110 are suitable for roll-up applications. Roll-up doors are well known in the trucking and transport industries, and have been commonly utilized on the rear and sides of trailers and truck exteriors.
Systems for displaying advertising images on the exterior of moving vehicles such as vans, trucks, and trailers have been developed in response to ever-increasing demand for innovative advertising media. In addition to direct application of the advertisement to the vehicle exterior by painting or otherwise directly applying an adhesive film containing an advertisement, display systems have been developed wherein a sheet containing an advertisement is removably attached to the exterior surface of the vehicle. Such systems allow for removal of the advertisement without damage to the vehicle and allow rapid conversion between advertising displays. However, as most such systems utilize flexible advertising displays, maintenance of a consistent and controlled tension within the panel is critical, as excessive tension may cause failure of the panel or mounting hardware, and insufficient tension may allow sag, flutter, damage, or dislocation of the panel under use conditions.
Prior art mobile advertising display systems are not ideal for use in applications in which variations in tension across the panel are frequent. For instance, prior art systems are not tailored for use on a roll-up trailer door, such as one in which a segmented door that is substantially flat in the closed position is rolled along a curved path in reaching its open position. Prior art systems have the disadvantage that they were not designed to provide adequate release and restoration of tension within the display panel to allow retraction of the roll-up door without causing tearing or other damage to the display panel or failure of the mounting hardware.